Move DD4hepSimulation.py and RunProg.py to DDSim folder
Rename RunProg.py to ddsim
Add cmake install for DD4hepSimulation to lib/python, ddsim to bin which is already in PATH

 - fix ignoring input lines with 'nan'
 - did not work on SL6 w/ gcc

 Added one more if statement: If the track went into new Volume, then extracted the hit in previous Volume, and start a new hit in this current Volume. And in this current process, also allow the same following treatments for the new hit.